The firmware is responsible for initializing the hardware and performing a POST (Power-On Self Test).

−

The firmware looks for the boot partition in nvram.

+

The default boot volume is stored in NVRAM and can be configured through the "Startup Disk" preference pane or the nvram command line utility [https://developer.apple.com/library/mac/documentation/Darwin/Reference/Manpages/man8/nvram.8.html]. Additional boot arguments can be provided via the "boot-args" value [http://www.cnet.com/news/boot-argument-options-in-os-x/].

Mac OS X extends EFI with a read-only HFS+ driver. According to [http://refit.sourceforge.net/info/boot_process.html] HFS+ volume header fields are used to point to a "blessed file" to be loaded as an EFI application. Though it is not clear which header field the source is referring to.

+

+

The firmware start the Mac OS X boot loader (boot.efi). The bootloader displays a dark grey Apple logo on the screen and loads the Darwin kernel from disk, as well as the essential driver extensions.

+

+

The bootloader can be eithe a MZ-PE/COFF or EFI fat binary type [[Executable|executables]] and is commonly stored in:

<pre>

<pre>

/com.apple.recovery.boot/boot.efi

/com.apple.recovery.boot/boot.efi

/System/Library/CoreServices/boot.efi

/System/Library/CoreServices/boot.efi

/usr/standalone/i386/boot.efi

/usr/standalone/i386/boot.efi

+

</pre>

+

+

The behavior of the bootloader can be configured in the com.apple.Boot.plist [https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man5/com.apple.Boot.plist.5.html] which can be found in:

+

<pre>

+

/Library/Preferences/SystemConfiguration/

</pre>

</pre>

Revision as of 11:56, 25 June 2014

Please help to improve this article by expanding it.
Further information might be found on the discussion page.

Apple Inc.'s Macintosh OS X (pronounced "OS Ten") is the operating system distributed with Apple computers. It includes heavily used several programs by default, including Apple Mail, a web browser called Safari, and an Apple Address Book, and iCal.

EFI boot

The firmware is responsible for initializing the hardware and performing a POST (Power-On Self Test).

The default boot volume is stored in NVRAM and can be configured through the "Startup Disk" preference pane or the nvram command line utility [1]. Additional boot arguments can be provided via the "boot-args" value [2].

Mac OS X extends EFI with a read-only HFS+ driver. According to [3] HFS+ volume header fields are used to point to a "blessed file" to be loaded as an EFI application. Though it is not clear which header field the source is referring to.

The firmware start the Mac OS X boot loader (boot.efi). The bootloader displays a dark grey Apple logo on the screen and loads the Darwin kernel from disk, as well as the essential driver extensions.

The bootloader can be eithe a MZ-PE/COFF or EFI fat binary type executables and is commonly stored in:

HFS/HFS+ date and time values

In HFS+ date and time values are stored in an unsigned 32-bit integer containing the number of seconds since January 1, 1904 at 00:00:00 (midnight) UTC (GMT). This is slightly different from HFS where the date and time value are stored using the local time. The maximum representable date is February 6, 2040 at 06:28:15 UTC (GMT). The date values do not account for leap seconds. They do include a leap day in every year that is evenly divisible by four. This is sufficient given that the range of representable dates does not contain 1900 or 2100, neither of which have leap days. Also see: Technical Note TN1150 - HFS Plus Volume Format